Halovinyl aldehydes: useful tools in organic synthesis

A transition metal-free [3 + 2] cycloaddition approach for the efficient synthesis of trisubstituted pyrrole derivatives from β-chlorovinyl aldehydes

A transition metal-free, Cs2CO3-promoted approach has been devised for the efficient synthesis of nitrile-substituted novel pyrrole derivatives from β-chlorovinyl aldehydes. Interestingly, the strategy was also found to be applicable to the synthesis of chromenone-fused pyrrole derivatives. The reaction proceeded through [3 + 2] cycloaddition between diversely substituted aryl propiolonitriles and toluenesulphonylmethyl isocyanide in DMF at ambient temperature. This approach offers several advantages including the use of inexpensive and readily available starting materials, wide substrate scope, operational simplicity, short reaction times (15 min-1.5 h), high atom economy, sustainable reaction conditions and high product yields. The strategy has been found to be amenable for gram-scale synthesis, and the scope of the strategy has been demonstrated for the synthesis of a diverse library of novel pyrrole derivatives with yields of up to 91%. The generated pyrrole derivatives are amenable for late-stage functionalisation and functional group interconversion.

Partial reductions of carboxylic acids and their derivatives to aldehydes

Recent advances in partial reductions of inert carboxylic acids and their derivatives to active aldehydes are reviewed.

α-Functionally Substituted α,β-Unsaturated Aldehydes as Fine Chemicals Reagents: Synthesis and Application

α-Functionalized α,β-unsaturated aldehydes is an important class of compounds, which are widely used in fine organic synthesis, biology, medicine and pharmacology, chemical industry, and agriculture. Some of the 2-substituted 2-alkenals are found to be the key metabolites in plant and animal cells. Therefore, the development of efficient methods for their synthesis attracts the attention of organic chemists. This review focusses on the recent advances in the synthesis of 2-functionally substituted 2-alkenals. The approaches to the preparation of α-alkyl α,β-unsaturated aldehydes are not included in this review.

Nickel catalyzed synthesis of 4,4′-bichromenes/4,4′-bithiochromenes and their Atropisomerism

4,4′-bichromenes and 4,4′-bithiochromenes have been synthesized by a Ni catalyzed homocoupling method and their Atropisomeric behavior has been studied.

An unexpected route to aldehyde-decorated single-chain nanoparticles from azides

A new route towards the straightforward synthesis of aldehyde-decorated ultrafine single-chain nanoparticles from azides is described.

Pyrido[1,2-a]pyrimidinium ions--a novel bridgehead nitrogen heterocycles: synthesis, characterisation, and elucidation of DNA binding and cell imaging properties

A novel class of bridgehead nitrogen heterocycles, pyrido[1,2-a]pyrimidinium ions, has been readily synthesized by a two-step one-pot reaction in high yields (up to 93%). These ionic compounds are bench stable and moisture tolerant and have highly fluorescent properties (quantum yield up to 0.65). A characteristic bright bluish fluorescence was observed in polar solvents such as acetonitrile and fluorescent intensity gradually diminishes with decreasing the polarity of the medium, which becomes almost negligible in toluene. These compounds also show interesting bioactivity. DNA interaction, imaging, and viability experiments with human leukemic Jurkat and KG-1A cells revealed that they are potential candidates for cancer diagnosis.

Use of isomeric, aromatic dialdehydes in the synthesis of photoactive, positional isomers of higher analogs of o-bromo(hetero)acenaldehydes

A series of photoresistant, positional isomers of o-bromo(hetero)acenaldehydes containing RO-Ar and bifunctional ortho-CHO/Br structural motifs, is available in the peculiar Friedel–Crafts modification, using isomeric aromatic o,o-dibromodialdehydes.

Concise synthesis of semicarbazides and formylhydrazines via direct addition reaction between aromatic azoarenes and N-substituted formamides

The addition reactions between aromatic azoarenes and N-substituted formamides are described.

Synthesis of substituted styrenes and 3-vinylphenols using ruthenium-catalyzed ring-closing enyne metathesis

The synthesis of substituted styrenes 3 and 3-vinylphenols 9 was achieved by ring-closing enyne metathesis (RCEM)/dehydration of 7 and RCEM/tautomerization of 8, respectively. Those methods provide selective access to unique aromatic compounds and solve the problem of regioisomer formation.

Efficient sonochemical synthesis of alkyl 4-aryl-6-chloro-5-formyl-2-methyl-1,4-dihydropyridine-3-carboxylate derivatives

A facile, efficient and environment-friendly protocol for the synthesis of 6-chloro-5-formyl-1,4-dihydropyridine derivatives has been developed by the convenient ultrasound-mediated reaction of 2(1H)pyridone derivatives with the Vilsmeier-Haack reagent. This method provides several advantages over current reaction methodologies including a simpler work-up procedure, shorter reaction times and higher yields.